This project has two components. Component 1 proposes to complete data collection in a complex, longitudinal study requiring six cohort interviews, as well as fully analyze the entire data set. The sixth of an integrally-designed set of six interviews will be completed in the first year of the continuation and the following two years will be devoted to intensive analysis of the resulting data set, consisting of seven interviews, completed at nin-monthly intervals over 4.5 years, on a cohort of approximately 2,500 women as they entered and experienced the menopause. The original aims to fully describe the epidemiology of the menopause--its relation to health, employment, life situation and life-style behaviors--will be addressed in the analysis. Component 2 consists of a five year, supplemental study of bone density changes on approximately 475 of the cohort, living in the Boston area and pre- or peri-menopausal at the time of the sixth Cohort Interview. This study compoent is proposed in conjunction with an already funded study of the same sub-sample of 475 women, which focuses on hormone changes over the same five year period. The purpose of this component is to describe, for the first time, bone density changes transmenopausally in a normal population and to identify pssible sub-groups at risk to very rapid bone loss.